Method for driving piles



ec., 69 E966 R. G. HINDMAN yggm METHOD FOR DRIVING' PILES Filed March18, 1964 2 SheetS-Sheeb l FIG. vI.

-DRIVING HEAD FILL-UP LINE f E ig ELECTRICAL LEAD To PUMP ADJUSTABLEPLATFORM DRIVEN PILE f-INVHAL SECTION Mun LINE Dec. 6, 1166 R. G. Hmm/ANMETHOD FOR DRIVING PILES 2 Sheets-Sheet 2 Filed March 18, 1964 DRIVING KV HEAD g/ INVENTOR.

FIG-2.

CENTRALIZER of qlc.;

ROBERT @.HINDMAN,

W j f l M., XJ

r VULLXL* United States Patent O 3,289,421 METHOD FOR DRIVING PILESRobert G. Hindman, New Orleans, La., assgnor, by mesue assignments, toEsso Production Research Company, Houston, Tex., a corporation ofDelaware Filed Mar. 18, 1964, Ser. No. 352,922 8 Claims. (Cl. 6153.74)

The present invention generally concerns the construction of drillingplatforms and particularly, the manner of forming foundations for suchdrilling platforms.

In driving piles, especially those to be used to carry offshore drillingstructures, by ordinary hammer means adequate pile penetrations cannotbe achieved in dense sands because of the great buildup ofend bearing onthe piles in the sand formation. Pile driving in such sands oftenresults in premature refusal, particularly for tension or holddownrequirements.

The invention to be described herein overcomes the disadvantagesinherent in ordinary pile driving techniques and achieves deeppenetrations of piles into dense sand formations with a minimum of piledriving difliculty.

In accordance with the invention, pilings such as steel tubings -orcylinders are driven with a hammer in a conventional way whilesimultaneously jettng water into the sand into which the piling isdriven to reduce the resistance to pile penetration. A pump is used todrive and force the water into the sand while new sections of pile arebeing added, as Well as when the pile sections are being driven into thesand.

A primary object of the invention is to provide an improved method andapparatus for driving piles into dense sands utilizing a water-jet lineyfor jetting water into the sands that is capable of continuousoperation.

The above and other objects and advantages of the invention will beapparent from the following, more detailed description thereof whentaken with the drawings in which:

FIG. 1 is a side elevation partially in section of apparatus embodyingthe invention and illustrating driving of the piles;

FIG. 2 is an elevational view of the jet-line assembly (and the pump) ofthe present invention;

FIGS. 3 and 4 are side elevations partly in section of a pile to bedriven into the underlying sand and illustrating positioning of thejet-line assembly and its action in accordance with the method of theinvention; and

FIG. 4A is a side elevation of the upper end of FIG. 4 illustrating thedriving head and anvil welded to the pile sections.

In the drawings, FIG. l shows a barge on which is mounted a platform 11and a crane 12 from which is suspended a steam hammer 13 used to drivepiles 14 into the dense sand formation below the less dense sand or mudzone 16. Barge 10 oats on water 17. One pile has peen driven through torefusal and the other pile consisting of an initial pile section 14a andan upper, new pile section 14b is shown in position to be driven intosand formation 15 by means of a driving head 18 on which is mountedsteam hammer 13. The sections of piling are welded together and todriving head 18 as indicated at 19.

FIGS. 3 and 4 show pile section 14a in position for penetration intosand formation 15. In FIG. 3 a jet-line pump assembly 20 is shown beingwashed downwardly through zone 16 in pile section 14a. Assembly 20, asshown more clearly in FIG. 2, includes a tubular member 21 provided withan inverted submersible pump 22 at its upper end and perforations 23adjacent its lower end. Tubular member 21 is provided with centralizersprings or arms 21a. An inlet screen 24 is provided on the suc-3,289,421 Patented Dec. 6, 1966 tion end of pump 22. A high pressurepump cutoff switch 25 is arranged on pump 22 and a spring-loaded checkvalve 26 is arranged on tube 21 below the pump 22. A pickup bale 27 isconnected to the upper end of assembly 20 to aid in placing it Withinand removing it from pile 14. Driving head 18 is provided with a cableport 30 containing a wire line pressure packing means 31 to seal off anelectrical cable 32 as it passes from the exterior of driving head 18 tothe interior thereof where it is connected to pump 22. Cable 32 connectsto a power source at the surface for supplying power to operate pump 22.A water ll-up port 33 is also formed in driving head 18. The upperportion of driving head 18 forms an anvil for contact with the steamhammer.

Assembly 2t) is self standing during driving operations by means of thecentralizers 21a. A plate 34 seals the anvil portion 18a of driving head18 from the interior thereof.

In operation, referring particularly to FIGS. 1 and 3, the initialsection of pile 14a is welded to the lower end of driving head 18 andsection 14a is driven by means of hammer 13 downwardly to the hard,dense sand formation 15. When pile section 14a reaches refusal in sands15, pile driving hammer 13 is removed from the pile and jet-line pumpassembly 2()` is inserted in the top of pile section 14a and loweredinto it by a line connected to bale 27. Cable 32 is connected to pump 22prior to lowering the assembly in the pile. Water, illustrated as at 35,is supplied to the interior of piling 14a through the upper end thereof.The Water is supplied to pile 14a until its level is above the pump 22.The pump is then operated and water is pumped through tubular member 21and out perforations 23 to wash assembly 20 through the soft sand andsilt 16 to the hard-packed sand 15 below it. The assembly may be forceddown by means not shown if the weight of the assembly and the washingaction does not cause it to move down. While this operation is beingperformed, a new pile section 14b is welded to the lower end of drivinghead 18 and positioned above section 14a. Then the surface end ofelectrical lead 32 is disconnected from the source of power to which itis connected and the lead is run through section 14b and head 18, andthrough opening 30 where it is packed olf by packing means 31. Lead 32is then reconnected to the power source on barge 10. This is done sothat the pump may continue to run while the new pile section 14b isbeing welded in position to the top of pile section 14a. After the twosections have been welded together, steam hammer 13 is lowered onto thetop of driving head 18. At this time the water level may be raised intosection 14b, if desired, through fill-up line 33.

Driving with steam hammer 13 is then commenced with pump 22 inoperation. Resistance to driving of the pile 14 is reduced by thejetting action of the water through jet-line pump assembly 20 whichpermits additional penetration of the pile. During driving operations,the water level in the pile is maintained above the level of pump 22through iill-up hose 33.

It is possible to continue taking suction (taking into consideration thedesign of the pump) at the higher pressure maintained by the waterwithin pile 14 during driv` ing and upstage this pressure for jetting.The assembly operates, then, as during welding, providing greater jetpressure than where hydrostatic pressure alone is used.

Also, it is possible to operate by hydrostatic pressure alone when thewater pressure within the piling is suiciently great. The waterproof,pressure-activated switch 25 cuts out and turns pump 22 olfautomatically without surface control. When the pressure dropssufficiently, switch 25 turns pump 22 on. When the pump is turned olf,fluid entry to tubular member 21 is through the spring-loaded checkvalve 26.

The technique of the present invention overcomes disadvantages in theuse of hydrostatic pressure alon-e to jet water through perforations 23.Where hydrostatic pressure alone is used, jetting must be stopped duringthe periods when the lead pile sections and driving head are rewelded tothe driven piling. At this time sand tends to plug the jet-line tube andto tighten about the piling which greatly increases driving resistance,barge time, and total costs. The Welding period may take from one andonehalf to two hours for each pile. The inverted submersible pump 22maintains jet ow through perforations 23 throughout the welding period.

Additional sections of pile are added on and the process is continuouslyrepeated to achieve the desired pile penetration.

Driving head 18 is removed when necessary by cutting7 off its connectionto the last or new section of pile added l and welding the upper end ofthe next pile section added to the pile to the driving head.

Having fully described the nature, method, objects, and advantages of myinvention, I claim:

1. A method for driving tubular pile sections into the ground in asubstantially vertical direction in which a driving member adapted to beattached to a hammer is attachable to the upper end of each pile sectionto be driven comprising the steps of:

arranging in a longitudinally extending position in a previously drivenpile section below the level of a column of water contained in said pilesection a tubular means provided with perforations at its lower end anda pump at its upper end;

attaching a new pile Section to said driven pile section;

attaching said driving member to the top of said new pile section; and

then hammering said driving member and said attached pile sections intothe ground While simultaneously operating said pump to pump watercontained in said pile sections through said tubular means and out saidperforations.

2. A method as recited in claim 1 in which new pile sections are addedwhere necessary by disconnecting said driving member, attaching a newpile section to said drivin g member, and then attaching the new pilesection to the driven pile section to which said driving member had beenattached.

3. A method as recited in claim 2 in which said pump is operated to pumpwater through said tubular means While said pile sections are beingattached to each other and while said driving member is beingdisconnected from and attached to pile sections.

4. A method as recited in claim 3 which includes the steps of addingwater to said pile sections to raise the level of water above the levelof said pump an amount suflicient for hydrostatic pressure to stopoperation of said pump and open a valve in said tubular means to permitwater to flow through said tubular means and jet through saidperforations under hydrostatic pressure alone.

5. A method as recited in claim 1 in which said pile sections are driveninto the ground underlying water in which a more dense formationmaterial underlies a zone of less dense material including the steps of:

driving piling to refusal through said zone of less dense material priorto the step of positioning said tubular means in said pile section;

removing said driving member; and

then after positioning said tubular means in said pile section,operating said pump to circulate water through said tubular means andsaid perforations to wash said tubular means downwardly within saidpiling to the lower tip thereof through said less dense material.

6. A method as recited in claim 5 in which new pile sections are addedwhere necessary by disconnecting said driving member, attaching a newpile section to said driving member, and then attaching the new pilesection to the driven pile section to which said driving member had beenattached.

7. A method as recited in claim 6 in which said pump is operated to pumpwater through said tubular means while said pile sections are `beingattached to each other and while said driving member is beingdisconnected from and attached to pile sections.

8. A method as recited in claim 7 which includes the steps of addingwater to said pile sections to raise the level of water above the levelof said pump an amount suicient for hydrostatic pressure to stopoperation of said pump and open a valve in said tubular means to permitwater to ow through said tubular means and jet through said perforationsunder hydrostatic pressure alone.

References Cited by the Examiner UNITED STATES PATENTS 911,971 2/1909Gilbreth 61-53.74 X 955,729 4/1910 Welsh 6l-53.74 X 3,215,201 ll/l965Lacy et al. 175-67 X CHARLES E. OCONNELL, Primary Examiner.

JACOB SHAPIRO, Examiner.

1. A METHOD OF DRIVING TUBULAR PILE SECTIONS INTO THE GROUND IN ASUBSTANTIALLY VERTICAL DIRECTION IN WHICH A DRIVING MEMBER ADAPTED TO BEATTACHED TO A HAMMER IS ATTACHABLE TO THE UPPER END OF EACH PILE SECTIONTO BE DRIVEN COMPRISING THE STEPS OF: ARRANGING IN A LONGITUDINALLYEXTENDING POSITON IN A PREVIOUSLY DRIVEN PILE SECTION BELOW THE LEVEL OFA COLUMN OF WATER CONTAINED IN SAID PILE SECTION A TUBULAR MEANSPROVIDED WITH PERFORATIONS AT ITS LOWER END AND A PUMP AT IS UPPER END;ATTACHING A NEW PILE SECTION OF SAID DRIVEN PILE SECTION; ATTACHING SAIDDRIVING MEMBER TO THE TOP OF SAID NEW PILE SECTION; AND THEN HAMMERINGSAID DRIVING MEMBER AND SAID ATTACHED PILE SECTIONS INTO THE GROUNDWHILE SIMULATANEOUSLY OPERATING SAID PUMP TO PUMP WATER CONTAINED INSAID PILE SECTIONS THROUGH SAID TUBULAR MEANS AND OUT SAID PERFORATIONS.